Troubleshooting hints for the low power (1 to 5W ) RT9000 Radio Telephone

Symptoms Potential problems Remedy

Display not working, wrong digit displayed

Cracked solder joints Resolder display
All LED's are on when powering on unit Reset Generator defective Replace U 24
Nothing comes on at power up check fuses, Reset generator Replace fuses, replace U24 reset gen.
U22 gets hot Latches defective Replace U4, U8
Cracked solder joints on display
No receive, no techmode control Ribbon cable between radio and interface board is twisted out of it's zero

insertion force connector

Remove the interface board and re-insert the cable straight into the connector
Cannot align audio levels properly An updated radio is used together with a non updated controller board

An updated radio can be recognized by an 18K resistor standing on edge

on the interface board and on an updated Rev 6 controller board R41 is 3.9K

Non updated controller boards where
Unit does not power up, on LED blinks Small red power wire is squeezed between radio chassis and main chassis Remove radio and re-route the red power lead to the other side

behind the 26 pin ribbon cable to prevent it from accidentially shorting

Scrambler not working Rev 6 and earlier controller boards can have erratic scrambler operation if the MX631 SPM detector

U36 is not installed. On later boards a 100K resistor is placed between pins 1 and 2 of U32 to remedy

this problem.

Install U36 or place a 100K resistor between pins 1 and 2 of U32.